KsProxy

KsProxy.ax is the Microsoft provided DirectShow filter which is used to capture streams of video from all varieties of WDM capture devices.  It is also used for DVD playback, and can host some specialized kernel KS filters such as MsTee, and various kernel audio components.  

KsProxy is a generic streaming engine.  It exposes pins, streams, and property sets based on the capabilities of the underlying WDM driver.

• User mode pins represent kernel streams.  Actual data transport can be either in user mode or kernel mode, depending on the capabilities of the filters at both ends of the connection.
• Property sets can be aggregated uniquely on each pin or on the filter as a whole.  When KsProxy instantiates in a graph, it queries the property sets supported by a WDM driver and searches for a corresponding COM interface to service the property set.
• Property pages can be aggregated uniquely on each pin or on the filter as a whole.
• Data handlers can be aggregated for each DataFormat during pin connection. Data handlers allow you to massage the data as it arrives from the capture device but before it flows through the downstream graph.

Microsoft DDK documentation which describes how to create property sets:

Win2000 DDK, Kernel Streaming Drivers, Design Guide, Part 4: Video Capture Drivers, 1.3.3 Custom Property Sets and Interfaces.

Adding custom property pages is fairly straightforward, while Data handlers are a bit more complex given the lack of documentation.